The invention relates to forming monolithic decorative surfaces on concrete walls, particularly pre-cast concrete walls, and, more particularly, pre-cast concrete road barriers of the type known as "New Jersey" style traffic barricade made of pre-cast reinforced concrete.
It has been known in the past to form surface ornamentations on concrete slabs, tiles, building structures and the like to simulate brick and stone wall. However, in the case of traffic barricades, for example, these have almost universally been of the typical light gray structures of the New Jersey style barricade with little or no surface ornamentation. When these structures are used to replace existing stone barriers, barricades and the like, while the safety features inherent in such structures is highly desirable, the drabness of such structures creates resistance to their use particularly in park areas and the like where a natural appearing structure is desirable. An object of the invention is to provide a cast concrete wall with a monolithically formed surface structure which has an aesthetically pleasing appearance at relatively low cost.
As noted above, there have been efforts in the past to provide concrete building walls, tiles, blocks with stone or block appearances. For example, in Dexter U.S. Pat. Nos. 836,368 and 748,352, concrete building walls, typically cast in situ are disclosed wherein a molding box having one side shaped in the form of building blocks has cast thereagainst the concrete to form the surface simulation of natural stone or block and, with particular reference to the present invention, in Dexter U.S. Pat. No. 836,368, a molding board is provided with a plurality of distributing fingers to prevent the coarser grades of concrete and gravel to be directed to the rear of the molding box which finer portions being distributed against the molding box which is to form the exposed viewing side of the wall. In Schillinger U.S. Pat. No. 88,747, the manufacture of artificial stone is disclosed in which coarser and finer facing material are mixed with coloring material or pigments and used as the facing materials used to fill the remaining part of the mold. In Henderson U.S. Pat. No. 909,792, a facing artificial stone is disclosed in which the facing material is placed into a molding box mold form and then a preferred concrete block is pressed onto the material in the mold until the final set of the facing material. Finally, in Chappell U.S. Pat. No. 957,188, an ornamental tile is formed by projecting upon a form cavity a plastic material which is caused to conform to a predetermined outline and which is allowed then to harden and against which a quantity of cementitious material which is adhesive to the first material is cast and allowed to harden.
According to the present invention, a mold is formed having ribs corresponding to the mortar joints desired in the final product and the ribs are coated with a retardant and then shielded by a shield having the outline or pattern of the mold joints. If a simulated stone wall is desired, the rib or mortar joint pattern is in the form of the perimeters of the "stone" and the sectors or spaces defined by the raised ribs defining the mortar joint can be blocked off between the masked areas. Pigmented cements, which are pigmented according to any desired color but a typical example for a "natural" stone wall will be (1) light brown, (2) dark brown and (3) dark gray and black. These pigmented cements are mixed, in receptacles and then individually sprayed as by gunnite type spraying apparatus, in the different mold sectors, the block outs being removed as each cement with its pigmentations are sprayed into the mold. Where the top "stones" in a horizontal wall section are being formed, a heavy bed of the same colored mortar and of the same consistency is applied in the mold in the sectors that ultimately form the top "stones". The masking material for the ribs forming the mortar joints is removed and the mortar joints then are sprayed with a mortar cement having the color of the joint desired in the wall being formed and may, of course, be a neutral gray mortar cement. If both sides of the concrete wall are to have "stone" facing, a second mold half is prepared in the same way and the two mold halves joined.
Then a reinforcing material such as a steel reinforcing cage or fabric is positioned in the mold and the mold is then filled with concrete prior to the setting or curing of any of the sprayed cements or colored cements. Care is taken to assure that the concrete that is loaded into the mold does not impinge with any force against the sprayed on pigmented cements to assure that the surface continuity of the "stone" is not disturbed in the mold. Typical molding procedures can be carried out such as the use of agitators and vibrators to reduce and eliminate air bubbles and to assure proper constant consistency in the concrete and also to assure a certain amount of admixing at the interface between the previously sprayed layers and coatings of cement and the concrete to assure the desired monolithticity in the final product. In addition, in the case of the New Jersey style road barriers, since it is cast upside down, with the top being at the bottom of the mold, wooden forms may be pressed into the concrete to form grooves and the like therein.
In a preferred embodiment of the invention, the wall sections have coupling elements formed in the ends thereof which are constituted by half conical projections and half conical recess formed in the ends of the walls or barricades.